Lucia's engagement was unilaterally broken off, and after being called a selfish and evil woman, she was given in marriage to Justo, the king of a neighboring country who is feared as the "devil". She had planned to spend her free time as a decorative queen, but she is now in love with Justo, who has turned into a doting lover. However, because they are both novices in love, they have yet to have their wedding night...? Meanwhile, Justo's cousin returns from studying abroad. Justo's cousin's cheerful and sociable personality, which is the complete opposite of Justo's, brings him closer to Lucia in no time, and Justo's love for Lucia explodes...? The cool king's sugar-coated love for Justo is so sweet that he can't keep his reason any longer! A sweet love fantasy of a timid duchess in love and a possessive king in reverse!